Submission #518429

#	Time	Username	Problem	Language	Result	Execution time	Memory
518429		Plurm	Carnival Tickets (IOI20_tickets)	C++17	0 / 100	1 ms	332 KiB

tickets

#include "tickets.h"
#include <bits/stdc++.h>
using namespace std;

long long find_maximum(int k, vector<vector<int>> x) {
	int n = x.size();
	int m = x[0].size();
	vector<vector<int>> answer;
	for (int i = 0; i < n; i++) {
		vector<int> row(m);
		for (int j = 0; j < m; j++) {
			row[j] = -1;
		}
		answer.push_back(row);
	}
  long long ans = 0ll;
  int lo = 0;
  int hi = 1e9;
  int mid;
  while(lo < hi){
    mid = (lo + hi)/2;
    int totcnt = 0;
    for(int i = 0; i < n; i++){
      int icnt = upper_bound(x[i].begin(),x[i].end(),mid) - x[i].begin();
      totcnt += icnt;
    }
    if(totcnt >= n*m/2){
      hi = mid;
    }else{
      lo = mid+1;
    }
  }
  int totcnt = 0;
  vector<int> negbar;
  for(int t = 0; t < k; t++){
    vector<int> idxs;
    for(int i = 0; i < n; i++) idxs.push_back(i);
    sort(idxs.begin(), idxs.end(), [&negbar](int x, int y){
      return negbar[x] < negbar[y];
    });
    vector<int> exact;
    for(int i = 0; i < n/2; i++){
      for(int j = m-1; j >= 0; j--){
        if(answer[idxs[i]][j] == -1){
          answer[idxs[i]][j] = t;
          exact.push_back(x[idxs[i]][j]);
          break;
        }
      }
    }
    for(int i = n/2; i < n; i++){
      negbar[idxs[i]]--;
      for(int j = 0; j < m; j++){
        if(answer[idxs[i]][j] == -1){
          answer[idxs[i]][j] = t;
          exact.push_back(x[idxs[i]][j]);
          break;
        }
      }
    }
    sort(exact.begin(), exact.end());
    for(int i = 0; i < exact.size()/2; i++){
      ans += exact[exact.size() - i - 1] - exact[i];
    }
  }
	allocate_tickets(answer);
	return ans;
}

Compilation message (stderr)

tickets.cpp: In function 'long long int find_maximum(int, std::vector<std::vector<int> >)':
tickets.cpp:62:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   62 |     for(int i = 0; i < exact.size()/2; i++){
      |                    ~~^~~~~~~~~~~~~~~~
tickets.cpp:33:7: warning: unused variable 'totcnt' [-Wunused-variable]
   33 |   int totcnt = 0;
      |       ^~~~~~

• Subtask 1: 0 / 11
• Subtask 2: 0 / 16
• Subtask 3: 0 / 14
• Subtask 4: 0 / 14
• Subtask 5: 0 / 12
• Subtask 6: 0 / 23
• Subtask 7: 0 / 10